import { useEffect, useRef, useState } from "react";
import { Link, NavLink } from "react-router-dom";

const menuData = [
  {
    key: "company",
    label: "Company",
    to: "/company",
    panelTitle: "PAL Networks",
    panelDesc: "회사 소개와 비전, 연혁, 파트너십 정보를 확인할 수 있습니다.",
    sections: [
      {
        title: "회사 소개",
        items: [
          { label: "회사소개", to: "/company/about", desc: "기업 철학과 핵심 가치" },
          { label: "연혁", to: "/company/history", desc: "주요 실적과 성장 과정" },
        ],
      },
      {
        title: "신뢰 정보",
        items: [
          { label: "고객 및 협력사", to: "/company/partners", desc: "주요 고객과 협력 네트워크" },
          { label: "찾아오시는 길", to: "/company/location", desc: "위치 및 연락처 안내" },
        ],
      },
    ],
    featured: {
      eyebrow: "About Us",
      title: "신뢰를 기반으로\n항공·플랫폼 기술을 확장합니다.",
      // text: "기업 소개 영역은 가볍게 보이지 않도록, 핵심 메시지와 신뢰 요소를 함께 노출하는 구성이 좋습니다.",
      cta: { label: "회사소개 보기", to: "/company" },
    },
  },
  {
    key: "uam",
    label: "UAM/UATM",
    to: "/uam",
    panelTitle: "UAM / UATM",
    panelDesc: "도심 항공 모빌리티와 통합 항공 교통 관리 기술을 소개합니다.",
    sections: [
      {
        title: "기술 소개",
        items: [
          { label: "UAM/UATM 소개", to: "/uam/intro", desc: "도심 항공 모빌리티 핵심 기술" },
          { label: "도입사례", to: "/uam/case", desc: "주요 도입 및 운영 사례" },
        ],
      },
    ],
    featured: {
      eyebrow: "Advanced Air Mobility",
      title: "안전한 하늘길,\n기술로 완성합니다.",
      text: "PAL Networks의 UAM·UATM 기술은 도심 상공의 안전 운항과 통합 관제를 실현합니다.",
      cta: { label: "UAM/UATM 보기", to: "/uam" },
    },
  },
  {
    key: "business",
    label: "Business",
    to: "/business",
    panelTitle: "Business Area",
    panelDesc: "구축부터 운영까지, PAL Networks의 종합 IT 서비스 역량을 소개합니다.",
    sections: [
      {
        title: "구축 · 개발",
        items: [
          { label: "System Integration", to: "/business/si", desc: "맞춤형 정보시스템 구축" },
          { label: "R&D", to: "/business/rnd", desc: "연구 개발 및 기술 고도화" },
        ],
      },
      {
        title: "운영 · 지원",
        items: [{ label: "운영 · 유지보수", to: "/business/maintenance", desc: "안정적인 시스템 운영과 사후 관리" }],
      },
    ],
    featured: {
      eyebrow: "Core Capability",
      title: "구축에서 운영까지,\n끝까지 책임지는 파트너.",
      text: "단순 납품이 아닌 장기 파트너십으로, 고객 시스템의 안정적 운영을 함께합니다.",
      cta: { label: "사업영역 보기", to: "/business" },
    },
  },
  {
    key: "solution",
    label: "Solution",
    to: "/solution",
    panelTitle: "Solution & Service",
    panelDesc: "산업별 솔루션과 서비스 포트폴리오를 확인하실 수 있습니다.",
    sections: [
      {
        title: "운영 솔루션",
        items: [
          { label: "비행상황관리 시스템", to: "/solution/flight-control", desc: "실시간 비행 상황 통합 관제" },
          { label: "IBE (Internet Booking Engine)", to: "/solution/ibe", desc: "항공 예약·발권 엔진" },
        ],
      },
      {
        title: "플랫폼 · 인프라",
        items: [
          { label: "스마트 관광 예약 플랫폼", to: "/solution/smart-tour", desc: "관광 예약 통합 운영 플랫폼" },
          { label: "KT G-cloud 인천총판", to: "/solution/kt-gcloud", desc: "공공 클라우드 인프라 공급" },
        ],
      },
    ],
    featured: {
      eyebrow: "Scalable Solutions",
      title: "검증된 솔루션으로\n비즈니스 가치를 만듭니다.",
      text: "운영 노하우가 축적된 자체 솔루션과 파트너십 기반 인프라를 함께 제공합니다.",
      cta: { label: "솔루션 보기", to: "/solution" },
    },
  },
  {
    key: "contact",
    label: "Contact Us",
    to: "/contact",
    panelTitle: "Contact Us",
    panelDesc: "프로젝트 문의와 인재 채용 정보를 확인하실 수 있습니다.",
    sections: [
      {
        title: "문의 및 채용",
        items: [
          { label: "문의하기", to: "/contact/inquiry", desc: "프로젝트 및 협업 문의" },
          { label: "채용정보", to: "/contact/recruit", desc: "함께할 동료를 찾습니다" },
        ],
      },
    ],
    featured: {
      eyebrow: "Get in Touch",
      title: "함께 만들어갈\n파트너를 기다립니다.",
      text: "프로젝트 협업이든 커리어든, 편하게 연락 주세요.",
      cta: { label: "문의 바로가기", to: "/contact/inquiry" },
    },
  },
];
export default function PalRenewalHeader() {
  const [activeMenu, setActiveMenu] = useState(null);
  const [isHeaderHover, setIsHeaderHover] = useState(false);
  const [isScrolled, setIsScrolled] = useState(false);
  const [isDarkHero, setIsDarkHero] = useState(false);

  const [isMobileMenuOpen, setIsMobileMenuOpen] = useState(false);
  const [mobileOpenKey, setMobileOpenKey] = useState(null);

  const closeTimer = useRef(null);
  const navRefs = useRef({});
  const mobileFirstFocusableRef = useRef(null);

  const activeData = menuData.find((item) => item.key === activeMenu);
  const showPanel = Boolean(activeData && !activeData.simple && isHeaderHover);

  useEffect(() => {
    const updateHeaderState = () => {
      const scrollTop = window.pageYOffset || document.documentElement.scrollTop || 0;
      const darkHeroActive = document.body.classList.contains("is-dark-hero");

      setIsDarkHero(darkHeroActive);
      setIsScrolled(!darkHeroActive && scrollTop > 80);
    };

    updateHeaderState();

    const observer = new MutationObserver(() => {
      updateHeaderState();
    });

    observer.observe(document.body, { attributes: true, attributeFilter: ["class"] });
    window.addEventListener("scroll", updateHeaderState, { passive: true });

    return () => {
      observer.disconnect();
      window.removeEventListener("scroll", updateHeaderState);
    };
  }, []);

  useEffect(() => {
    return () => {
      if (closeTimer.current) clearTimeout(closeTimer.current);
    };
  }, []);

  useEffect(() => {
    if (isMobileMenuOpen) {
      document.body.style.overflow = "hidden";

      const timer = setTimeout(() => {
        mobileFirstFocusableRef.current?.focus();
      }, 50);

      return () => {
        clearTimeout(timer);
        document.body.style.overflow = "";
      };
    }

    document.body.style.overflow = "";

    return () => {
      document.body.style.overflow = "";
    };
  }, [isMobileMenuOpen]);

  const clearCloseTimer = () => {
    if (closeTimer.current) clearTimeout(closeTimer.current);
  };

  const openMenu = (key) => {
    clearCloseTimer();
    setIsHeaderHover(true);
    setActiveMenu(key);
  };

  const scheduleClose = () => {
    clearCloseTimer();
    closeTimer.current = setTimeout(() => {
      setIsHeaderHover(false);
      setActiveMenu(null);
    }, 120);
  };

  const closeDesktopMenu = () => {
    setIsHeaderHover(false);
    setActiveMenu(null);
  };

  const closeMobileMenu = () => {
    setIsMobileMenuOpen(false);
    setMobileOpenKey(null);
  };

  const closeAllMenus = () => {
    closeDesktopMenu();
    closeMobileMenu();
  };

  const toggleMobileMenu = () => {
    setIsMobileMenuOpen((prev) => !prev);
  };

  const handleMobileAccordion = (key) => {
    setMobileOpenKey((prev) => (prev === key ? null : key));
  };

  const handleNavKeyDown = (e, index, item) => {
    if (e.key === "ArrowRight") {
      const nextItem = menuData[index + 1] || menuData[0];
      navRefs.current[nextItem.key]?.focus();
    }

    if (e.key === "ArrowLeft") {
      const prevItem = menuData[index - 1] || menuData[menuData.length - 1];
      navRefs.current[prevItem.key]?.focus();
    }

    if (e.key === "ArrowDown" && !item.simple) {
      e.preventDefault();
      openMenu(item.key);
    }

    if (e.key === "Escape") {
      scheduleClose();
    }
  };

  const isActiveHeader = isScrolled || showPanel || isMobileMenuOpen;
  const logoSrc = isActiveHeader || !isDarkHero ? "./images/pal_logo.png" : "./images/pal_logo_wh.png";

  return (
    <>
      <header className={`pal-header ${isScrolled ? "is-scrolled" : ""} ${showPanel ? "is-open" : ""} ${isMobileMenuOpen ? "is-mobile-open" : ""}`} onMouseEnter={clearCloseTimer} onMouseLeave={scheduleClose}>
        <div className="pal-header-inner">
          <h1 className="pal-header-logo">
            <Link to="/Main" onClick={closeAllMenus}>
              <img src={logoSrc} alt="PAL Networks" />
            </Link>
          </h1>

          <nav className="pal-gnb" aria-label="Primary Navigation">
            <ul className="pal-gnb-depth1">
              {menuData.map((item, index) => {
                const isActive = activeMenu === item.key;

                return (
                  <li
                    className={`pal-gnb-item ${isActive ? "is-active" : ""}`}
                    key={item.key}
                    onMouseEnter={() => {
                      if (!item.simple) {
                        openMenu(item.key);
                      } else {
                        clearCloseTimer();
                        closeDesktopMenu();
                      }
                    }}
                  >
                    {item.simple ? (
                      <NavLink
                        to={item.to}
                        className="pal-gnb-link"
                        ref={(el) => {
                          navRefs.current[item.key] = el;
                        }}
                        onClick={closeAllMenus}
                        onFocus={() => {
                          closeDesktopMenu();
                        }}
                        onKeyDown={(e) => handleNavKeyDown(e, index, item)}
                      >
                        <span className="pal-gnb-link-text">{item.label}</span>
                        <span className="pal-gnb-link-line"></span>
                      </NavLink>
                    ) : (
                      <button
                        type="button"
                        className="pal-gnb-link"
                        ref={(el) => {
                          navRefs.current[item.key] = el;
                        }}
                        aria-expanded={isActive}
                        aria-haspopup="true"
                        onFocus={() => openMenu(item.key)}
                        onClick={() => openMenu(item.key)}
                        onKeyDown={(e) => handleNavKeyDown(e, index, item)}
                      >
                        <span className="pal-gnb-link-text">{item.label}</span>
                        <span className="pal-gnb-link-line"></span>
                      </button>
                    )}
                  </li>
                );
              })}
            </ul>
          </nav>

          <div className="pal-header-util">
            <div className="pal-header-lang">
              <button type="button" className="is-active">
                KOR
              </button>
              <span className="pal-header-lang-divider">|</span>
              <button type="button">ENG</button>
            </div>

            <button type="button" className={`pal-header-hamburger ${isMobileMenuOpen ? "is-active" : ""}`} aria-label={isMobileMenuOpen ? "모바일 메뉴 닫기" : "모바일 메뉴 열기"} aria-expanded={isMobileMenuOpen} aria-controls="pal-mobile-menu" onClick={toggleMobileMenu}>
              <span></span>
              <span></span>
              <span></span>
            </button>
          </div>
        </div>

        <div
          className={`pal-mega-panel ${showPanel ? "is-visible" : ""}`}
          onMouseEnter={() => {
            clearCloseTimer();
            setIsHeaderHover(true);
          }}
          onMouseLeave={scheduleClose}
        >
          {activeData && !activeData.simple && (
            <div className="pal-mega-panel-inner">
              <div className="pal-mega-panel-intro">
                <span className="pal-mega-panel-eyebrow">{activeData.panelTitle}</span>
                <h2>{activeData.featured.title}</h2>
                <p>{activeData.featured.text}</p>
                <Link to={activeData.featured.cta.to} className="pal-mega-panel-cta" onClick={closeAllMenus}>
                  {activeData.featured.cta.label}
                </Link>
              </div>

              <div className="pal-mega-panel-content">
                <div className="pal-mega-panel-top">
                  <strong>{activeData.panelTitle}</strong>
                  <p>{activeData.panelDesc}</p>
                </div>

                <div className="pal-mega-panel-grid">
                  {activeData.sections.map((section) => (
                    <div className="pal-mega-section" key={section.title}>
                      <h3>{section.title}</h3>
                      <ul>
                        {section.items.map((item) => (
                          <li key={item.label}>
                            <Link to={item.to} className="pal-mega-item" onClick={closeAllMenus}>
                              <span className="pal-mega-item-title">{item.label}</span>
                              <span className="pal-mega-item-desc">{item.desc}</span>
                            </Link>
                          </li>
                        ))}
                      </ul>
                    </div>
                  ))}
                </div>
              </div>
            </div>
          )}
        </div>
      </header>

      <button type="button" className={`pal-header-dim ${showPanel ? "is-visible" : ""}`} aria-label="메뉴 닫기" onClick={closeDesktopMenu}></button>

      <div className={`pal-mobile-dim ${isMobileMenuOpen ? "is-visible" : ""}`} onClick={closeAllMenus}></div>

      <aside id="pal-mobile-menu" className={`pal-mobile-menu ${isMobileMenuOpen ? "is-open" : ""}`} aria-hidden={!isMobileMenuOpen}>
        <div className="pal-mobile-menu-head">
          <strong>MENU</strong>
          <button type="button" className="pal-mobile-menu-close" aria-label="모바일 메뉴 닫기" onClick={closeAllMenus} ref={mobileFirstFocusableRef}>
            <span></span>
            <span></span>
          </button>
        </div>

        <div className="pal-mobile-menu-body">
          <ul className="pal-mobile-nav">
            {menuData.map((menu) => {
              const isOpen = mobileOpenKey === menu.key;

              return (
                <li className={`pal-mobile-nav-item ${isOpen ? "is-open" : ""}`} key={menu.key}>
                  {menu.simple ? (
                    <Link to={menu.to} className="pal-mobile-nav-link" onClick={closeAllMenus}>
                      <span>{menu.label}</span>
                    </Link>
                  ) : (
                    <>
                      <button type="button" className="pal-mobile-nav-toggle" onClick={() => handleMobileAccordion(menu.key)} aria-expanded={isOpen}>
                        <span>{menu.label}</span>
                        <i className="pal-mobile-nav-arrow"></i>
                      </button>

                      <div className="pal-mobile-submenu">
                        {menu.sections.map((section) => (
                          <div className="pal-mobile-submenu-group" key={section.title}>
                            <h3>{section.title}</h3>
                            <ul>
                              {section.items.map((item) => (
                                <li key={item.label}>
                                  <Link to={item.to} className="pal-mobile-submenu-link" onClick={closeAllMenus}>
                                    <strong>{item.label}</strong>
                                    <p>{item.desc}</p>
                                  </Link>
                                </li>
                              ))}
                            </ul>
                          </div>
                        ))}

                        <Link to={menu.featured.cta.to} className="pal-mobile-featured-link" onClick={closeAllMenus}>
                          <span>{menu.featured.eyebrow}</span>
                          <strong>{menu.featured.cta.label}</strong>
                        </Link>
                      </div>
                    </>
                  )}
                </li>
              );
            })}
          </ul>

          <div className="pal-mobile-contact-box">
            <p>프로젝트 문의 및 협업 상담이 필요하시면 연락해 주세요.</p>
            <Link to="/contact" className="pal-mobile-contact-link" onClick={closeAllMenus}>
              Contact Us
            </Link>
          </div>
        </div>
      </aside>
    </>
  );
}